[Question] C++ Reference StaticMeshComponent

Development Programming & Scripting
1

I am having some trouble when trying to reference a StaticMeshComponent from a Blueprint. In short what I am trying to do is change the parameter of one of the materials, that part works fine. But when I try to then apply the material to the mesh I crash, I did now add in a check for my pointer and I am not crashing anymore but I am not sure what I am doing wrong exactly.

.h
// Copyright 1998-2013 Epic Games, Inc. All Rights Reserved.

#pragma once

#include "VLight.generated.h"

/**
 * 
 */
UMaterialInstanceDynamic* LightMID;

UCLASS()
class AVLight : public AActor
{
	GENERATED_UCLASS_BODY()
	
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=Materials)
	UMaterialInterface* Base_Material;

	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=Meshes)
	UStaticMeshComponent* VaMesh;

public:

	virtual void PostInitializeComponents() OVERRIDE;
};

.cc

// Copyright 1998-2013 Epic Games, Inc. All Rights Reserved.

#include "MyGamemode.h"
#include "VLight.h"


AVLight::AVLight(const class FPostConstructInitializeProperties& PCIP)
	: Super(PCIP)
{
	
}

void AVLight::PostInitializeComponents()
{
	Super::PostInitializeComponents();
	

	LightMID = UMaterialInstanceDynamic::Create(Base_Material, this);
	LightMID->SetVectorParameterValue(FName(TEXT("Colour")), FLinearColor(1000,0,0,1));
    //For Testing only
    If(!VaMesh)return;	
    VaMesh->SetMaterial(1, LightMID);//Crashes
  }
2

You have a c++ error

this

//For Testing only
    If(!VaMesh)return;  
    Mesh->SetMaterial(1, LightMID);//Crashes

should be this

//For Testing only
    If(!VaMesh)return;  
    VaMesh->SetMaterial(1, LightMID); //Happy

Make sure to modify the comment for good luck

3

That was corrected and the material is still not being applied.

4

Are you sure you want to set the second material (index 1)? Shouldn’t it be the first material (SetMaterial(0, LightMID))?

5

Yeah, I wish to apply the material in the second slot, I have also tried applying it to slot 0 but I am getting the same results.

6

are you sure that you are setting Base_Material in your BP for this class?

Does it show up in the blueprint defaults as a colored box / the image preview shows a material?

Rama

7

Yep that is working, I appears to be a problem either in my blueprint or the script. I can’t even run a GetMaterial for the mesh.

8

Try this:

UMaterialInstanceDynamic* LightMID = VaMesh->CreateAndSetMaterialInstanceDynamic(1);
LightMID->SetVectorParameterValue(FName(TEXT("Colour")), FLinearColor(1000.f,0.f,0.f,1.f));

VaMesh should have your Colourable material already applied.

9

That works, but that was not the problem. I finally got it working now, I had the mesh itself setup all wrong. It was not receiving the correct data from the BP of the class. I had to change some stuff in my .h file and it is all working now. Thank you everybody for your help!

10

could you post the corrected header file ?